Chromosomal location of homeobox genes and related genes.

<p>The HOX cluster genes are indicated. PRD domain only encoding genes are marked in blue, the TALE gene <i>psa-3</i> that lost its homeobox is marked in green, and the <i>ocam-1</i> gene is marked in yellow. Clusters of homeobox genes are described in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0126947#pone.0126947.t003" target="_blank">Table 3</a>. Noteworthy are the grouped genes on the left arm of chromosome II, i.e., <i>ceh-81</i> to <i>ceh-87</i> and <i>duxl-1</i>. Most of these genes are all highly divergent, except <i>ceh-81</i> and <i>ceh-82</i>, which show similarity to each other. Many have multiple homeoboxes, and most do not have an ortholog in other <i>Caenorhabditis</i> species, except <i>ceh-87</i>.